Freiburg 2024 – scientific programme
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A: Fachverband Atomphysik
A 5: Ultra-cold Plasmas and Rydberg Systems I (joint session A/Q)
A 5.7: Talk
Monday, March 11, 2024, 18:30–18:45, HS 1010
Ultrafast excitation of dense Rydberg gases at the threshold to ultracold plasma — •Jette Heyer1,2, Mario Großmann1,2, Julian Fiedler1,2, Markus Drescher1,2, Klaus Sengstock1,2, Philipp Wessels-Staarmann1,2, and Juliette Simonet1,2 — 1The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany — 2Center for Optical Quantum Technologies, University of Hamburg, Hamburg, Germany
Ultrashort laser pulses enable the local ionization of a quantum gas on femtosecond time scales. By tuning the central wavelength of a single laser pulse of 166 fs duration across the two-photon ionization threshold of 87Rb, we investigate the transition from ultracold plasma to dense Rydberg gases.
Above this threshold, strong-field ionization triggers the formation of a highly charged ultracold plasma. Below the ionization threshold, we observe the ultrafast formation of dense Rydberg gases as the Rydberg blockade is bypassed by the large bandwidth of the femtosecond pulse. Charge-imbalanced microplasma dynamics prevent Rydberg recombination close to the threshold and leads to ionization of deeply bound Rydberg states even far below the threshold.
Our experimental setup allows us to directly detect the energy distribution of ions and electrons as well as Rydberg atoms. State of the art molecular dynamics simulations give us insight into the underlying dynamics of the many-body system, which is governed by long-range Coulomb interactions.
Keywords: Bose-Einstein condensates; Ultrafast laser pulses; Rydberg excitations; Ultracold atoms; Strong-field ionization